ReiserFS V3 is the stablest Linux filesystem, and V4 is the fastest.
In regards to claims by ext2 that they are the de facto standard
Linux filesystem, the most polite thing to say is that many persons
disagree, and it is interesting that those persons seem to include
the distros that are growing in market share. See
http://www.namesys.com/benchmarks.html for why many disagree.